ABSTRACT Heart failure with reduced ejection fraction (HFrEF) affects roughly 3 million in the U.S. and is a mortal and morbid disease. HFrEF impairs a patient's ability to exercise and perform activities of daily living. Although weak cardiac pumping ability clearly contributes to chronic disability associated with HFrEF, abnormal skeletal muscle in patients with HFrEF is also a key debilitating factor. Skeletal muscle is therefore a vital target for treatment of HFrEF. Inorganic nitrate enhances aerobic exercise capacity and muscle power in preliminary studies of patients with HFrEF. The overarching aim of our study (and the follow-up randomized clinical trial [RCT]) is to determine whether inorganic nitrate offers a new, safe and effective treatment for ameliorating the disability due to HFrEF. The Specific Aims of this study are 1) to determine the best dose of inorganic nitrate for patients with HFrEF; 2) to determine the best primary endpoint (aerobic capacity or muscle power) and the number of patients that will be needed for the RCT; and 3) to set up the infrastructure and manuals needed for standardized performance of the RCT protocols across multiple medical centers. For Aim 1, the effects of 10mmol and 20mmol of KNO3 vs. placebo on hemodynamics, and blood levels of nitrate and nitrite and breath NO will be measured and any side effects noted. In Aim 2, a small, phase II clinical trial of 2 wk of KNO3 treatment (dose determined by Aim 1) in a randomized, placebo-controlled, non-crossover design study will be performed. The endpoints of this aim will be aerobic capacity (peak oxygen consumption ? VO2peak), measured during treadmill exercise using a metabolic cart and peak quadriceps muscle power measured using a Biodex machine. In Aim 3, all of the infrastructure needed for the RCT will be constructed. A RedCAP? database for data entry, storage, and export from all RCT sites will be created. All Cores (Data Coordinating Center, Imaging Analysis Core, Laboratory Core, Exercise Analysis Core, Pharmacy Core) for the RCT will be established and Manuals of Operation will be written. The potential impact of finding a new, safe and effective treatment that helps millions of patients beat the disability of HFrEF is enormous.